The present invention relates to systems for the transmission of commands to peripheral means, particularly to motor-driven transport means and principally to automatic carriages on rails for the overhead conveyance of materials, wherein a main station is provided that generates and sends command signals to the peripheral means which house on-board receiving and handling circuits for the command signals.
Many methods and devices are known for the remote control of apparatus or machines driven by electric motors.
For example, in the field of materials handling in manufacturing industries, it is necessary to use methods and devices for the remote control of the functions inherent to the operations carried out by vehicles moved by electric motors, particularly those running on rails.
In these cases, several transmission lines (cables, rails, bus-bars) are often used which transmit the command signals generated by control apparatus located at a ground station to the self-propelled vehicle through sliding contact brushes.
One is dealing, for example, with commands for starting, changing from one speed to another, slowing, stopping, reversing, the carrying out of various operative functions by tools mounted on the motor-driven transport means themselves.
In the example of an application to self-propelled carriages on rails, the bus-bars are generally fixed to the core of the rail carrying it or to a flat strip or other support located above or the side of the rail, a common arrangement, for example, in cases in which the self-propelled vehicle is a bridge crane or other translatory machine.
When the number of commands to be transmitted is considerable, the number of conductors or bus-bars also increases. Difficulties are thus generated in the arrangement of the bus-bars, particularly in the case of the arrangement of the conductors on the core of the slide rail for an overhead self-propelled system where the conductors for supplying the drive motors of the individual carriages must also be housed.
In the case of self-propelled carriages on rails, the need has now been reached to arrange 7, 8, 9 and up to 10 bus-bars or the like, with the disadvantage that, because of the limited dimensions of the rail profile, it is necessary to limit the maximum number of bus-bars which can be housed and hence the number of commands which can be given.
Sometimes recourse is made to external auxiliary command lines if the functions to be controlled exceed those that can be controlled by the number of bus-bars which can be housed along the core of the rail and, moreover, attempts are made to produce extremely compact assemblies to the detriment of the ease of installation and maintenance.
If it were wished to use remote control systems with electromagnetic signals instead of bus-bars, however, it would be necessary to mount complex receiving circuits on the self-propelled carriages, while the system itself would also be exposed to the industrial environment where it would be prone to serious malfunctions because of the noise and electromagnetic interference created by the other equipment in operation.